AeroElectric-List Digest Archive

Wed 07/20/11


Total Messages Posted: 3



Today's Message Index:
----------------------
 
     1. 07:04 AM - Re: Load Analysis Spread Sheet (Bill Watson)
     2. 01:21 PM - Batteries: To fly . . . or not to fly . . . that IS the question. (Robert L. Nuckolls, III)
     3. 02:03 PM - Re: Batteries: To fly . . . or not to fly . . . that IS the question. (Bill Watson)
 
 
 


Message 1


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    Time: 07:04:56 AM PST US
    From: Bill Watson <Mauledriver@nc.rr.com>
    Subject: Re: Load Analysis Spread Sheet
    There's more electrical system wisdom condensed in Bob's post than you'll glean in 2 weeks of surfing! do not archive I'm forced to reflect on it all after driving my Maule into RDU yesterday, having lunch, and then requiring a 'jump' to get out! What happened? I've been flying around with a marginal battery. It was marginal at my annual a few weeks ago but it was not noticed. Since then, I've flown it every day and noted that the solenoid sometimes didn't always engage on the first try so it's totally my bad at this point. But I was getting it started each time... until I sat on the ramp for 5 mins running the panel while talking to RDUclearance delivery. By the time I tried to start.... buzz buzz, but no click. I slinked into the FBO and asked for a jump. After a bit, a lineman showed up with a cart but alas, I have no plug and the oil access hatch doesn't really give access to the battery. He tsk tsk'd me and observed we couldn't remove the cowling to start it if your battery is really dead. He was giving me an up and down look as I looked at this grizzled lineman wondering what we would do amidst all the whining turbines. I mumbled that hand propping could work but assumed policy prohibited such antics at big airport FBO. He looked at my well worn mount, noted the pilot door removed for summer comfort, and seemed to note the paint and oil stains on my shorts. Looking over his shoulder he said, "let's prop it then". I have limited experience with propping but know that the 'propper' is placing a good bit of trust in one's teammate. I assumed he knew what he was doing and he assumed I knew what I was doing and off we went. He said "prime it". I said, "it doesn't need much", knowing that just 1 throttle pump would be needed at this particular point. He gave the appropriate mags on and mags off commands, I repeated them loudly and hand signalled them for insurance. Took 3 pulls and off I went. Back in the system, I was queued behind a Tobago for takeoff. The controller was familiar enough with the 2 of us to give the Tobago clearance for runway heading and had me rolling just as his wheels left the ground. I got an immediate right turn on course to cross the parallel. I wrapped it up tight and crossed before midfield as he cleared 2 aircraft on the parallel then finally right turned the Tobago on course after airliners landed and took off the parallel. I was in the home pattern before the Tobago caught up. That was cool! Bill "still driving the Maule but feeling the '10" Watson On 7/19/2011 7:15 PM, Robert L. Nuckolls, III wrote: > <nuckolls.bob@aeroelectric.com> > > At 02:32 PM 7/19/2011, you wrote: >> You are going thru the same process as all of us have. Look at >> everything you can find, steal as much as can and along the way >> you'll get you're head wrapped around it. > > Agreed. Many builders start with a strong urge to "keep > everything running" in spite of inevitable failures of all kinds. > By inevitable failure I mean no piece of hardware on your > airplane has an infinite service life, nor are any components > immune to the effects of error in craftsmanship or degraded > performance due to misunderstanding or neglect. The short > version of this idea is "Things Break". > > Suggest you review the article on Failure Modes Effects > analysis at: > > http://www.aeroelectric.com/articles/Failure%20Modes%20Effects%20Analysis.pdf > > > also chapter 17 in the 'Connection > > Then figure out what you plan to do personally to > deal with the failure of any device or system in the > airplane. It's easy to spend hours, pounds and dollars > designing an electrical system that will keep every > device in the airplane POWERED while ignoring the > non-zero probability that that coveted system is not > immune from FAILURE. > > I've mentioned many times here on this List that > my personal approach to flying airplanes (always > rental machines) is to be prepared to aviate and navigate > and navigate to airport of intended destination > in what I call "The J-3 Mode". Toward that end my > flight bag has always included . . . > > http://aeroelectric.com/Pictures/Misc/Vacination_for_Dark_Panel_Syndrom.pdf > > > My goals for having confidence to operate my airplane- > of-the-day is predicated on the idea that at best I'll get > there as long as the engine runs and the flight > controls stay hooked up. At worst, I'll get an > adventure on some airport I never before intended > to visit. > > For anyone setting out to configure their electrical > system, the first question is, "Can I operate this > airplane in the vast majority of anticipated missions > with the master switches OFF?" > > If the answer to that is "yes", then I'll suggest > that your extra-ordinary needs for electrical energy > are small to zero. If "no", then what's the practical > solution to making sure the MINIMAL compliment of > additional hardware is powered up for longer than > you have fuel to keep the engine running? > > Start with solving that problem first. What is your > MINIMALIST plan and skill set for comfortable > termination of flight and figure the energy budget > for delivering to that plan? > > If any of those equipment items are necessary for > keeping the engine running they should be powered from > a battery bus. In other words, if you've got > smoke in the cockpit, you should be able to > turn the master switch OFF and STILL continue > to airport of intended destination. > > After conducting this exercise, then figure out > how many more electro-whizzies you'd like to > have running, not for necessity but for convenience. > Any airplane can be successfully operated to a > comfortable arrival with ZERO engine instrumentation > . . . if you want to take the time to learn how > to do it. An airplane can be successfully navigated > with ZERO panel mounted nav-aids. Communication is > a driving consideration only during the approach to > landing phase and this can be done with a hand-held. > > After figuring out how you will achieve this level > of confidence and competence with the manner in which > you intend to use your airplane, then decide what > your dollar, weight and volume budget is for adding > more "stuff". > > This exercise goes to two important points. Only > a tiny fraction of unhappy days in the cockpit have > roots in electrical system failures. The vast majority > of unhappy days in the cockpit have roots in poor > piloting skills usually combined with poor decision > making processes in dealing with what should be > a no-big deal failure. > > If things didn't break on airplanes, FBO's would be > out of business. Only YOU can make sure the majority > if not all of your failures are a maintenance event > as opposed to an emergency arising from lack of > skill/planning. > > After this thought exercise you are now properly informed > to carry out a load analysis that will drive architecture, > weight, system complexity, and cost of ownership. > The short review for all the above is, "Please disabuse > yourself of the notion that backups to backups is > any sort of replacement for understanding your machine, > it's limitations and your own limitations. Tony Levier > in a '60 model C-172 is a lot less likely to suffer > a bad day in the cockpit than most of today's pilots > buying a Malibu or A-36 with all the goodies. > > Some of my most enjoyable cross countries were conducted > in the J-3 mode. Go down low, get out the maps, punch > up a destination on the $100 hand held GPS and shut all > the rest of that stuff off. If you can do it for fun, you > can do it when conditions demand it. > > > Bob . . .


    Message 2


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    Time: 01:21:22 PM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Batteries: To fly . . . or not to fly . . . that IS
    the question. At 09:01 AM 7/20/2011, you wrote: > >I'm forced to reflect on it all after driving my Maule into RDU >yesterday, having lunch, and then requiring a 'jump' to get out! >What happened? I've been flying around with a marginal battery. It >was marginal at my annual a few weeks ago but it was not noticed. Toward mitigating that condition, consider acquiring one of these critters . . . Emacs! http://tinyurl.com/3gnnwrt This is a carbon-pile load tester for large batteries. While not a substitute for a real capacity test, the load tester will give you a bench-mark for the battery's ability to get the engine started. A carbon-pile is a special kind of high current, adjustable resistor. http://aeroelectric.com/Pictures/Battery_Testers/HF91128_0.jpg The big-momma clips are hooked to the battery termnials, you punch the button on the 15 second timer and then quickly crank the knob clockwise until the voltmeter drops to the level appropriate to the battery's temperature. http://aeroelectric.com/Pictures/Battery_Testers/HF91129_4.jpg Do the best you can to hold the voltage at that level. When the 15 second timer beeps, observe the current reading and quickly back off the load. That carbon pile is only good for a few seconds at those power levels and will probably "stink". Generally speaking, if the ammeter shows less than 200 amps after 15 seconds, its time to replace the critter. Clipped right across the battery terminals with the engine running at an RPM where the alternator is expected to provide full output, you can put the load tester across the battery and crank the current up until the bus voltage drops to 13.0 volts (battery isn't delivering or taking on energy). The reading on the meter PLUS any loads in the airplane you can't turn off is the output current of your alternator. This is a lot of testing bang for the buck. Bob . . .


    Message 3


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    Time: 02:03:33 PM PST US
    From: Bill Watson <Mauledriver@nc.rr.com>
    Subject: Re: Batteries: To fly . . . or not to fly . . . that
    IS the question.




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